Apparatus for folding envelope flaps

ABSTRACT

A machine for making envelopes or the like is provided with an apparatus for folding the sealing flaps of envelopes or for folding other articles having transversely extending folds which includes a rotary folding cylinder having several rows of suction holes as well as pairs of folding rollers having suction holes for folding the flap of each envelope taken over by a row of suction holes of the folding cylinder.

United States Patent Inventor Kurt Stemmler Rhine, Germany Appl. No. 750,929 Filed Aug. 7, 1968 Patented Jan. 26, 1971 Assignee Winkler & Dunebier Maschinenfabrik und Eisengiesseri Neuwied am Rhine, Germany a corporation of Germany Priority Aug. 17, 1967 Germany W44575 APPARATUS FOR FOLDING ENVELOPE FLAPS 6 Claims, 3 Drawing Figs.

U.S. Cl

Int. Cl B3lb 1/12, B3lb2l/26, B31b41/26 Field of Search 93/27, 61,

[56] References Cited UNITED STATES PATENTS 1,894,726 1/1933 Beckman... 93/27X 2,047,710 7/1936 Schwartz 270/69 2,244,723 6/1941 Novick 93/61 2,671,385 3/1954 Johenning.. 93/84 2,822,733 2/1958 Williams 93/61 2,880,656 4/1959 Welsh 93/61 3,088,382 5/1963 Winkler 93/62 3,097,578 7/1963 Winkler 93/62 3,316,819 5/1967 Cohn.......... 93/62 3 ,400,642 9/1968 Stemmler 93/62 Primary ExaminerWayne A. Morse, Jr. Attorney-Richards & Geier ABSTRACT: A machine for making envelopes or the like is provided with an apparatus for folding the sealing flaps of envelopes or for folding other articles having transversely extending folds which includes a rotary folding cylinder having several rows of suction holes as well as pairs of folding rollers having suction holes for folding the flap of each envelope taken over by a row of suction holes of the folding cylinder.

PATENTED mes l9?! sum 1 0F 2 Inventor Kstcmmler mfgvhwdgt T I'LNEBS 7 Since, in the directionxof movement, the still open sealing flap isto the rear, the already folded middle part of the .envelope is, for folding of thesealing flap, deflected out of its direction of movement, and the sealing flap held by suction apertures near the prepared folding line'is drawn, together with the middle part, between two rollers in such a way that the entire envelope passes throughthe two rollers with the folding line to the front. g

The known apparatuses which-operate reliably at low outputs of envelopes per minute, cannot be usedfor the currently required deliveryrates-of over 1,000 envelopes per minute. Even in the case of heavy duty apparatuses, difi'iculties arise at exaggerated quantities per minute. Since the sealing flap is normally sharply creased, the rollersfor folding the same must have only a slight gap between them or even exerta resilient pressure on each other. However, a certain quantity of air is always contained in the previously folded middle partjof the envelope. lnview of the rapid passage of the envelope of FIG. 1. is a longitudinal section through the apparatus, taken along the line [-1 in FIG. 2; I

FIG. 2 is a cross section through the apparatus taken along the line ll-ll in FIG. 1; and

FIG. 3 is a plan view (development) of the folding cylinder, seen in the direction of the arrow G in FIG. 2, without the parts disposed outside of the folding cylinder The main parts of the apparatus are a folding cylinder 1, a feed roller 2, a deflecting roller 3 and a discharge roller 4. These parts are mounted to rotate in the sidewalls 5, 6 of the machine and are driven in a manner not shown but at the same peripheral speed, in the direction of the arrows shown in the drawing. 1

The main part of the folding cylinder 1 is a cylinder 7 on which axle journals 9, 10 are secured by bolts 8. The axle journals are mounted to' rotate in the sidewallsS, 6, in antifriction bearings l 1," and are secured in a manner not shown to prevent longitudinal displacement. Evenly distributed on the periphery of the cylinder 7 are-five pairs of folding rollers l2, l3, rotatably mounted in bearings 14, which are secured on the cylinder 7 by means of bolts 16. Together with their bearings, the folding rollers are so disposed in grooves 17 of the cylinder 7 that the folding rollers touch the theoretical outer surface of the cylinder 7 from within. The folding rollers l2, 13 of each pair are set sufficiently apart from each other to allow passage of the envelope which is to be folded.

which the sealing flap is to be folded, between the very closely set folding rollers, the airno longer has any time to escape and thus can result in the bursting of the envelope. Or, altematively, it is essential to dispense with the desired sharp crease of the sealing flap. Furthermore, there is the danger, if the middle part of the envelope is reversed out of its position forwards in the direction of movement into a rearward position in the direction of movement, without being reliably guided, that the envelope will be displaced or may become completely detached from the, suction apertures holding the sealing flap near the fold line and will fly out ofthe machine.

An object of the .presentinvention is an apparatus which does not have the aforesaid'disadvantages and which permits a sharp creasing of the sealing flap at anoutput of far more than 1,000 envelopes per minute. l

Other objects of thepresent invention will become apparent in the course of the following specification.

In the accomplishment of the objectives of the present invention it was found advisable to provide an apparatus in which there are provided, evenly distributed over the periphery of a rotating folding cylinder, a plurality of rows of suction holes, each rowbeing adapted to hold, close to its leading edge (viewed in the direction of feed), an envelope fed to the following cylinder; the said apparatus also has, likewise evenly distributed over the periphery of the folding cylinder, in each case between two rows of suction holes, a pair of oppositely controlled folding cylinders with suction holes for folding the sealing flap of each envelope taken over by the preceding (in the direction of feed).ro w of suction holes from the folding cylinder.

Each of the envelopeswhich is fed individually at regular intervals and which is ready folded exceptfor the sealing flap which is to the rear, when viewed in the direction of feed, is first gripped close to its front edge by a row of suction holes and then also gripped, close behind the prepared line along which the sealing flap is to be creased, by the suction holes of t a pair of folding cylinders,,dra'wn approximately 5 mm-deep in between the. rotating folding cylinders and thereby sharply creased along its sealingflap, after which the middle part of the envelope which is securely gripped between the folding cylinders is folded over the sealing flap. Upon their later reverse rotation, the folding cylinders release the ready folded?0 envelope. I The invention willappear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example, a preferred embodiment of the inventive idea.

In the drawings:

Rotatably mounted on the axle journals 9, 10 are stellate arm assemblies 18, 19, on the five arms of which, evenly distributed, five suction strips 20 with covers 21 are secured by means of bolts 22. To accommodate the suction strips 20, the cylinder 7 has recesses 23 which are covered by a plurality of narrow arcuate bridges 24. Appropriate recesses 26 are provided in the suction strips 20 to accommodate the bridges 24. The outer faces of the suction strips 20 and of the bridges 24 form a part of the shell of the cylinder 7.

The broad recesses 23 in the cylinder 7 make it possible to vary the distance between a suction strip 20 and the subsequent pair of folding rollers 12, 13 by jointly pivoting the arm assemblies l8, 19 about the axle journals 9, 10. A bolt 27 which engages in an arcuate slot 28 in the arm assembly 19, serves to arrest the arm assemblies together with the, suction strips 20. Each suction strip has a row of suction holes 20 which are provided with nipples 30 made from rubber or the receive suction air intermittently in a manner to be described hereinafter through a channel 31 which is closed by the cover 21 and a bore 32 in the arm assembly 18.

The folding rollers 12, 13 of each pair of folding rollers engage with each other by meshing teeth 33 and can consequently only rotatein opposite directions. Mounted on the long journal 34 of each folding roller 13 is a crank 35 carrying a bolt 36 with a rotatable roller 37. The roller 37. is drawn continuously against a cam 39 by a spring 38 engaging on the bolt 36, the cam 39 being mountedby means of bolts 40 on the sidewall 5 and being so -formed that it causes each pair of rollers to carry out a partial movement of approximately and back while the sealing flap of one envelope is being-folded.

Each folding roller 12 has a row of suction holes 12' which receive, in a manner to be described hereinafter, intermittent supplies of suction air through a longitudinal bore 42 in the folding roller, sealed at the end by a plug 41, and through a bore 43 in the bearing 15 and the cylinder 7. Each folding roller 13 has a row of suction holes 13' which receive suction air intermittently through longitudinal bore 44 in the folding roller and a bore 45 in the cylinder 7. The suction holes l2, 13' of each pair of folding rollers are deflected radially from the rotary center of the cylinder7 until such time as an envelope is attracted by suction.

To control the suction air at the suction holes 20' of the suction strip 20, a rotary slide valve 49 is provided which is mounted to pivot on the axle journal 9, being secured in a longitudinal direction by means of an adjusting ring 50. Screwed rigidly into the rotary valve 49 is a bolt 51 over which engages an eyebolt 52, the threaded end of which engages through a bore in a bolt 53 which is rotatably mounted in the sidewall S. The rotary slide valve 49 is secured against rotating with the folding cylinder by two nuts 54 on the threaded end of the eyebolt 52 and is angularly adjustable within certain limits. The rotary slide valve 49 has an arcuate control slot 55 which is connected to a suction air line 56 so that the suction holes 20' of each suction strip 20 receive suction air so long as the mouth 32' of the associated bore 32 is situated in front of the control slot 55, as can be seen from FIGS. 1 and 2.

To control the suction air at the suction hole 12 of the folding roller 12 or the hole 13 of the folding roller 13, a rotary slide valve 59 is provided which is mounted to pivot on the axle journal 10, being secured in a longitudinal direction by an adjusting ring 60. The rotary slide valve 59 is secured against rotating together with the folding cylinder by a bolt 61, an eyebolt 62, a bolt 63 and nuts 64 and is angularly adjustable, in the same manner as described for the control slide valve 49. The rotary slide valve 59 has two control slots 65 and 66 situated on different radii, both control slots being connected to a suction air line 67. The suction holes 12 of each folding roller 12 receive suction air through the control slot 65 so long as the mouth 43' of the associated bore 43 is situated in front of the control slot 65. The suction holes 13 of each folding roller 13 receive suction air through the control slot 66 so long as the mouth 45' of the associated bore 45 is situated in front of the control slot 66.

The feed roller 2 has two oppositely situated rows of suction holes 2' and 2", which each alternately feed one envelope to the folding cylinder 1. The deflecting roller 3 has a row of suction holes 3', the discharge roller 4 a row of suction holes 4'. The suction air at the suction holes 2', 2", 3' and 4 is controlled in known manner and is not illustrated or described in greater detail.

Secured above the folding cylinder 1 on the sidewalls 5, 6 is a bridge 68, expediently pivotable upwardly in a manner not shown. Mounted on this bridge by means of bolts 73 are guides 69 for the envelopes, with flanges 70, and guides 71 with flanges 72. Longitudinal slots 74 provided in the bridge 68 for passage of the bolts 68 allow a lateral displacement of the guides on the bridge according to the width of the envelopes to be folded.

Between the feed roller 2 and the guides 69 are guides 75 which are held by eyes 76 on a rod 77 rigid on the sidewalls 5, 6. The guides 75 engage expediently into grooves 78 on the periphery of the feed roller 2 as supports for the envelopes.

Mounted on the outer end of the axle journal 9 is a half coupling 80, secured against twisting by a key 81. It is connected by bolts 82 to a half coupling 83 mounted rigid on a drive shaft 84 and secured against twisting by a key 85. The half coupling 83 has arcuate slots 86 through which can pass bolts 82. Thus, the folding cylinder 1 is angularly adjustable in relation to the rollers 2, 3 and 4 to allow adjustment to the size of the envelopes to be folded. To facilitate this adjustment, a scale 87 is provided on one of the half couplings.

As can be best seen in FIG. 3, the apparatus for folding the sealing flap of an envelope E is so adjusted that the fold line F of the envelope E which is gripped by the suction holes 20 just to the rear of its front edge, comes to be situated a dimension D (equal to approximately mm.) behind the suction holes 13' of the folding roller 13 which are directed radially away from the pivot point of the folding cylinder. Suction holes which are not covered by the envelope are sealed in a manner known per se by plugs or by adhesive masking.

The operation is as follows:

An envelope E arriving on the feed roller 2 is held just behind its front edge by suction holes 2' and is taken over just behind its front edge by a row of suction holes of the folding cylinder, the suction holes 20' at this moment receiving suction air through the control slot 55; the drawings show the position of the folding cylinder and of the feed roller 2 shortly after the suction holes 20 of the folding cylinder have taken over an envelope E. Upon further rotation of the folding cylinder, the prepared folding line F of the sealing flap of the envelope comes to rest to the extent of the length D behind the suction holes 13 of the folding roller 13 (FIG. 3). The suction holes 13' now receive suction air through the control slot 66, grip the envelope and shortly afterwards the suction holes 20' release the front edge thereof once again. Now the rising cam 39 starts to rotate the folding rollers 12, 13, this being the position B of the folding rollers (FIG. 2). As soon as the front edge of the envelope arrives under the deflecting roller 3, it is gripped by the suction holes 3' therein and carried away upwardly by the folding cylinder. The folding rollers 12, 13 have now completed their partial rotation of approximately 90, the sealing flap of the envelope is sharply creased between them, along the prepared fold line F. In the position of the folding rollers under the deflecting roller 3, shown in FIG. 2, the suction holes 12' of the folding roller 12 are receiving suction air through the control slot 65, whereas the suction holes 13 of the folding roller 13 are disconnected from the suction air. The suction holes 3 of the deflecting roller 3 release the upwardly entrained front edge of the envelope E" after approximately 90 rotation of the deflecting roller. With further rotation of the folding cylinder 1, the middle part of the envelope, securely held between the folding rollers, is moved rearwardly over the sealing flap; then, by reason of the falling cam 39, the folding rollers again rotate back into their starting position in which they now only hold the envelope E by the suction holes 12' of the folding roller l2,just behind the fold line of its forward sealing flap. As soon as the envelope arrives under the discharge roller 4, it is taken over by the suction holes 4' therein and discharged.

The number of pairs of folding rollers 12, 13 evenly distributed over the folding cylinder 1, and also the number of rows of suction holes 20' disposed in each case between two pairs of folding rollers may be less more more than five. The higher the number, the longer the time available for folding the individual envelope, in relation to the cadence of the machine.

Instead of the common rigid bearings 14, 15 for the pairs of folding rollers l2, l3, movable, spring-loaded bearings may be provided for one folding roller of each pair of folding rollers, expediently for folding roller 12, if it is desired always to achieve the same pressure between the folding rollers in spite of the machine processing envelopes made from different thicknesses of paper. Instead of a row of suction holes 20' adjustable in their distance from the associated pair of folding rollers, according to the length of the envelope to be folded, it is possible to dispose in the shell of the folding cylinder 1 a plurality of stationary rows of suction holes, of which in each case only those are used which correspond to the length of the envelope to be folded, while the other rows of such holes are closed. Furthermore, the apparatus of the present invention is not confined to the folding of envelope flaps but may be used for the folding of other articles having transversely extending folds. All such and other variations and modifications are to be included within the scope of the present invention.

lClaim:

1. An apparatus for folding the sealing flap of an envelope having a fold line between the sealing flap and the envelope body, said apparatus comprising a rotary folding cylinder having means forming a plurality of rows of suction holes upon said cylinder, means supplying suction to said holes for holding the envelope, pairs of folding rollers carried by said cylinder, each pair being located between two rows of said suction holes, said folding rollers having suction holes, a deflecting roller located close to said folding cylinder and having suction means, means rotating the two folding rollers of each pair in opposite directions to each other and reversing these directions at predetermined intervals, and means supplying suction to the suction holes of the folding rollers at intervals corresponding to the first-mentioned intervals, whereby during one said interval opposed suction holes of the two folding rollers of each pair move inwardly and cause the fold line of an envelope to be sucked in and folded between said two v folding rollers, the fold of envelope being thereupon moved outwardly by the rotation of said two folding rollers in the opposite direction. the body of the envelope being held by said deflecting roller during the folding. I

2. An apparatus in accordance with claim 1, comprising rotary stellate arm assemblies, the means forming suction holes upon said folding cylinder comprising rigid suction strips evenly distributed on said stellatearm assemblies concentrically withsaid folding cylinder, said stellate arm assemblies being rotatable along with said suction strips,

' 3. An apparatus in accordance with claim 1, comprising arcuate envelope-guiding guides located above a portion of said folding cylinder. a y

4.-An apparatus in accordance with claim 1, comprising rnovable spring-loaded bearings for.one of each pair of folding separate crank firmly connected with one roller of each pair of trolled oppositely directed partial rotation of substantially 90 back and forth for each full rotation of the folding cylinder.

6. An apparatus in accordance with claim 5, wherein the means causing the partial rotation of the rollers comprise a folding rollers, a rotatable roller connected with said crank, a fixed control cam, and a springv connected with said crank and pressing the last-mentioned roller against said cam. 

1. An apparatus for folding the sealing flap of an envelope having a fold line between the sealing flap and the envelope body, said apparatus comprising a rotary folding cylinder having means forming a plurality of rows of suction holes upon said cylinder, means supplying suction to said holes for holding the envelope, pairs of folding rollers carried by said cylinder, each pair being located between two rows of said suction holes, said folding rollers having suction holes, a deflecting roller located close to said folding cylinder and having suction means, means rotating the two folding rollers of each pair in opposite directions to each other and reversing these directions at predetermined intervals, and means supplying suction to the suction holes of the folding rollers at intervals corresponding to the first-mentioned intervals, whereby during one said interval opposed suction holes of the two folding rollers of each pair move inwardly and cause the fold line of an envelope to be sucked in and folded between said two folding rollers, the fold of envelope being thereupon moved outwardly by the rotation of said two folding rollers in the opposite direction, the body of the envelope being held by said deflecting roller during the folding.
 2. An apparatus in accordance with claim 1, comprising rotary stellate arm assemblies, the means forming suction holes upon said folding cylinder comprising rigid suction strips evenly distributed on said stellate arm assemblies concentrically with said folding cylinder, said stellate arm assemblies being rotatable along with said suction strips.
 3. An apparatus in accordance with claim 1, comprising arcuate envelope-guiding guides located above a portion of said folding cylinder.
 4. An apparatus in accordance with claim 1, comprising movable spring-loaded bearings for one of each pair of folding rollers.
 5. An apparatus in accordance with claim 1, wherein the means rotating the folding rollers comprise meshing teeth carried by the two rollers of each pair and means connected with said teeth and cAusing each pair of rollers to carry out a controlled oppositely directed partial rotation of substantially 90* back and forth for each full rotation of the folding cylinder.
 6. An apparatus in accordance with claim 5, wherein the means causing the partial rotation of the rollers comprise a separate crank firmly connected with one roller of each pair of folding rollers, a rotatable roller connected with said crank, a fixed control cam, and a spring connected with said crank and pressing the last-mentioned roller against said cam. 